Trolley shoe dressing device



y 1967 D. R. ROSS a 3,321,587

TROLLEY SHOE DRESSING DEVICE Filed Feb. 16, 1965 INVENTOR. DONALD A. Ross.

5 raeA/Js. Ys,

United States Patent 3,321,587 TROLLEY SHOE DRESSIN DEVICE Donald R. Ross, Pittsburgh, Pa., asslgnor to US. Electric Manufacturing Company, Pittsburgh, Pa., 3 partnership Filed Feb. 16, 1965, Ser. No. 433,132 7 Claims. (Cl. 19135) ABSTRACT OF THE DISCLOSURE A clip is attached to a trolley wire and is provided with laterally projecting side portions that dress the top of a grooved trolley shoe as the shoe slides along the bottom of the wire and across the bottom of the clip.

The trolley systems for electric cranes and the like include an electrical conductor or trolley wire, along the bottom of which a grooved shoe slides. The shoe picks up current from the wire and delivers it to an electric motor. It is common practice, and in some states it is even mandatory, to enclose the trolley and shoe in a guard to prevent accidental contact with the pair of electrical conductors. Such a guard is a non-metallic tubular member made of flexible material, through which the trolley wire extends and which the wire supports. To accommodate the shoe, the tubular guard extends a considerable distance below the wire, and to permit the trolley pole to move the shoe along the wire the tubular guard is split lengthwise along its bottom. Ordinarily, the edges of the split engage each other or overlap, but as the pole moves along they are forced apart temporarily by it for a short distance. The trolley shoe straddles the bottom of the trolley wire and is made of a material that wears away as the shoe slides back and forth along the wire. For example, the shoe may be made of a mixture of copper and graphite. As the shoe Wears, the trolley pole pushes it upward to hold it against the wire, so the wire extends deeper and deeper into the shoe. In other words, the shoe extends farther and farther up the opposite sides of the conductor as the shoe wears. This eventually may result in the upper outer edges of the shoe cutting into or through the upper part of the tubular guard.

It is among the objects of this invention to provide a device which will prevent a trolley shoe from engaging the upper part of the trolley wire guard, which can quickly be applied to a trolley wire, which operates automatically, and which is inexpensive and reliable.

In accordance with this invention, a trolley shoe dressing device is provided that has a central portion extending across the to of a trolley wire and rigidly fastened to it inside the tubular guard that is supported by the wire. The dressing device also has rigid side portions projecting laterally from opposite sides of the wire above its bottom. The lower surfaces of these side portions are abrasive, so that when the trolley shoe has worn sufiiciently to engage and slide across those surfaces, the top of the shoe will be dressed or worn away and thereby prevented from extending farther upward on the wire and possibly cutting the guard above it.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a fragmentary side view of a trolley wire and guard, with part of the guard broken away to show the trolley shoe and dressing device in elevation;

FIG. 2 is a vertical section taken on the line IIII of FIG. 1; and

FIG. 3 is a perspective view of the dressing device.

Referring to FIGS. 1 and 2 of the drawings, a trolley conductor or wire 1 is connected at its ends to suitable insulated supports (not shown). Electric current is delivered to the wire in a well-known manner. Between its ends, the wire may be supported at intervals by hangers 2 attached to suitable rigid brackets 3. Preferably, as shown in FIG. 2, the lower portion of the trolley wire is bulbous in cross section and the upper part has a flat t P, the two portions being tapered toward each other. Electric current is collected from the trolley wire by means of a trolley shoe 4 that slides along the bottom of the wire. The shoe is supported by a collector pole 5, which urges the shoe up against the wire. The top of the shoe is provided with a longitudinal groove 6 that receives the lower part of the trolley Wire so that the shoe will be guided along the wire.

The trolley Wire and shoe are covered by a tubular guard 8 that surrounds them. The guard hangs on the wire. It is made of flexible material, such as natural or synthetic rubber or a synthetic plastic. The hangers 2 clamp the upper part of the tubular guard against the opposite sides of the upper portion of the trolley wire. To permit the trolley pole to move the shoe along the wire, the guard tube is split lengthwise along its bottom. The edges of the split either engage each other or overlap, except in the immediate area of the shoe where the trolley pole spreads them apart. As the trolley wire wears the groove in the sliding shoe deeper, the shoe is moved upwardly on the wire by means of the pole, which keeps the shoe in contact with the bottom of the wire.

It is a feature of this invention that the wearing trolley shoe is prevented from extending up the sides of the wire far enough for the upper edges of the shoe to cut into the tubular guard and damage or ruin it. Accordingly, one or more dressing devices are mounted on the trolley wire for dressing or cutting or grinding away the top of the trolley shoe after the groove in the shoe has been Worn down to a predetermined depth. Preferably, as shown in FIG. 3, the dressing device is in the form of a metal clip 10 that extends across the top of the trolley wire. The clip may be provided with a central resilient downwardly-opening loop 11 for receiving the upper part of the wire and clamping onto it to hold the clip in stationary position. At the lower ends of the loop the clip has integral rigid side portions 12 that project laterally away from the trolley wire at an elevation close to the overlying portions of the tubular guard. This will locate the pro jecting side portions of the clips far enough up on the trolley wire to avoid being engaged by the sliding shoe until after the shoe has become worn considerably. After a sufiicient amount of wear of the shoe at its groove has occurred, the top of the shoe will be high enough up on the wire for it to engage the lower surfaces of side portions 12 of the clip as the shoe moves along the wire beneath the clip. The side portions of the clip may be provided with abrasive lower surfaces 13 in any suitable manner, so that as the trolley shoe slides across them they will wear or grind the top of it away. Or, if desired, the bottom of the clip may be smooth, but provided with knife edges at its opposite ends for shaving off the top of the trolley shoe. In either case, the clip will prevent the trolley shoe from extending so far up on the wire as to engage and cut into the portion of the guard directly above the shoe. Consequently, there is no danger of the guard being damaged by the shoe before the shoe has been replaced by a new one.

The dressing clip disclosed herein automatically dresses the trolley shoe every time the worn shoe passes under it. There is nothing to operate and nothing to get out of order as far as the clip is concerned. As many clips as desired can be used, but often one will be enough. The clip is easily applied to the trolley wire by merely pressing it down onto the wire to cause the central loop to snap over the upper part of the Wire. The clip is inexpensive and can quickly be replaced if necessary.

According to the provisions of the patent statutes, I

have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A trolley shoe dressing device having a central portion for attachment to an underlying trolley wire, and having side portions projecting laterally outward from said central portion formed to remove the top of the sides of a grooved trolley shoe sliding along the bottom of the wire and across the bottom of said device.

2. A trolley shoe dressing device according to claim 1, in which the lower surfaces of said side portions are abrasive.-

3. A trolley shoe dressing device in the form of a clip having a central resilient downwardly-opening loop for clamping onto the upper portion of a trolley wire, the clip also having rigid side portions projecting laterally outward from the lower ends of the loop, the lower surfaces of said side portions being engageable by the top of a grooved trolley shoe sliding along the bottom of the wire, and said side portions being formed to dress the top of the trolley shoe at opposite sides of the wire.

4. In combination with a trolley wire and a flexible split tubular guard containing the wire and supported by it, a dressing device inside the guard rigidly supported by the wire,--s aid device extending across the top of the wire and having rigid side portions projecting laterally outward from opposite sides of the wire above its bottom, and said side portions being formed for removing the top of a grooved trolley shoe at opposite sides of the wire when it slides along the bottom of the wire and across the bottom of said dressing device.

5. In combination with a trolley wire and a flexible split tubular guard containing the wire and supported by it, a metal clip inside the guard rigidly supported by the wire, the clip having a central downwardly-opening loop receiving the upper portion of the wire, the clip having rigid side portions projecting laterally outward from the lower ends of the loop above the bottom of the wire, and said side portions being formed for dressing the top of a grooved wearable trolley shoe at opposite sides of the wire when it slides along the bottom of the Wire and across the bottom of said device.

6. In the combination recited in claim 5, said loop being resilient and clamped tightly onto the wire.

7. In the combination recited in claim 5, said side portions having abrasive lower surfaces engageable by the top of a trolley shoe.

References Cited by the Examiner UNITED STATES PATENTS 2,481,194 9/1949 Bubb et a1. l9l35 ARTHUR L. LA POINT, Primary Examiner.

EUGENE G. BOTZ, Examiner.

S. B. GREEN, Assistant Examiner. 

1. A TROLLEY SHOE DRESSING DEVICE HAVING A CENTRAL PORTION FOR ATTACHMENT TO AN UNDERLYING TROLLEY WIRE, AND HAVING SIDE PORTIONS PROJECTING LATERALLY OUTWARD FROM SRAID CENTRAL PORTION FORMED TO REMOVE THE TOP OF THE SIDES OF 